Stop mechanism



p 1956 J. P. MACKIE 2,763,034

STOP MECHANISM Filed April 29, 1953 2 Sheets-Sheet 1 Inventor JOHN P. NACKlE m, 4! QM Attorney Sept. 18, 1956 J. P. MACKIE STOP MECHANISM 2 Sheets-Sheet 2 Filed April 29, 1953 United States Patent STOP MECHANISM John Pringle Mackie, Belfast, Northern Ireland, assignor to James Mackie & Sons Limited Application April 29, 1953, Serial No. 351,875 Claims priority, application Great Britain May 2, 1952 11 Claims. (Cl. 19-166) This invention relates to stop mechanisms for drawing frames and similar textile machines, such, for example, as spinning frames in which sliver or other fibrous material emerging from a drawing head then proceeds to a further stage of treatment. The use of a detector which bears directly on the sliver in a fixed position between the drawing rollers, and in a drawing frame, for example, the delivery rollers, and which serves to detect breakage of the sliver so as to operate a stop mechanism, is unsatisfactory for a number of reasons. The chief of these is that, particularly when the sliver is very fragile, the weight of the detector causes a gradual sag in the sliver, leading to a gradual build-up of vagrant fibres between the detector and the moving sliver. This may result in breakage of the sliver due to excessive friction and to the excessive bearing area thereby produced between the detector and the surface of the sliver.

According to the present invention, a pivoted detector is employed and repeated engagement is brought about between the detector and the sliver or other fibrous material, the motion causing this engagement having a component transverse to the general direction of travel of the sliver so that provided the sliver is moving at a speed greater than a critical value in relation to the transverse component of the relative motion, the detector is rocked about its pivot so as to prevent either the detector or a part acting with it from coming into either direct or indirect engagement with an abutment. Under normal operating conditions, the sliver will be moving at a speed greater than this critical value, but under other conditions when it is moving at a speed less than this value, it will fail to rock the detector about its pivot with the result that either the detector or the part acting with it will come into en agement with the abutment and will thus operate a stopping device. 1

With such an arrangement, there will be three distinct sets of conditions under which the detector is not rocked about its pivot and the stopping device is brought into action. The most common of these is when the sliver is either wholly or partly missing so that there is no engagement between the detector and the sliver and thus nothing to cause the necessary rocking action of the detector. Thus the stop mechanism will come into action as soon as the sliver is either partly or wholly missing. The mechanism will also come into action if the sliver is present, but is stationary, as is the case with a choke. In this event, the detector will engage the sliver in the usual way, but since it is not moving, it will not cause the necessary rocking action. The third and least common set of circumstances in which the stop mechanism will be brought into action is when the sliver is moving, but at a speed less than the critical value. This may occur under conditions known as a running choke when the sliver moves forward at a speed equal to the feed speed instead of the delivery speed of the drawing head.

Thus it will be understood that it is desirable to operate the stopping device as soon as the speed of the sliver falls below a certain critical value which can be determined in any particular set of circumstances. In designing the machine, the speed of relative motion causing the engagement between the detector and the sliver is so selected that the stopping device is brought into action as soon as the speed of the sliver falls below this critical value.

Most simply the motion necessary to bring'about the engagement is imparted to the detector member, which for this purpose may be caused to move in a closed path in such a way so as to engage the sliver repeatedly with a component of motion transverse to that of the sliver. Thus under normal operating conditions, as soon as the detector touches the sliver it will be rocked about its pivot as already described, while under other conditions, the detector or a part moving with it engages an abutment and so operates the stopping device. Preferably the abutment is fixed so that when the detector or the part moving with it engages the abutment, its motion is interrupted and this then operates the stopping device.

The motion of the detector may be transmitted from a driving member by way of a spring so that when the motion of the detector is stopped by means of engagement with the abutment, the spring is deformed and the relative movement between its ends is used to operate the stopping device.

As an alternative to bringing about engagement by means of movement of the detector, this may be occasioned by means of a transverse motion of the sliver imparted to it by means of a plate or other support over which it passes. In this case, the support causing the transverse motion may itself constitute the abutment. Thus if the pivot of the detector is normally stationary, as soon as the detector comes into engagement with the abutment, its pivot is displaced by means of the movement of the latter and this displacement is used to operate the stopping device.

'Forms of stop mechanism in accordance with the invention will now be described in more detail by way of example with reference to the accompanying drawings, in which:

Figures 1 and 2 are an elevation and a plan view respectively of the drawing head of a textile machine fitted with a stop mechanism in accordance with the invention;

Figures 3 and 4 are detailed views showing steps in the operation of the stop mechanism.

Figures 5 to 7 show successive steps in the operationof an alternative form of stop mechanism; and

Figure 8 shows a modification of the stop mechanism shown in Figures 1 to 4.

As seen in Figures 1 and 2, sliver 1 emerging from the gill bed, part of which is shown at 2, of a drawing frame passes between a drawing roller 3 and a correspondingpressing roller 4 to a pair of delivery rollers 5 and 6 respectively. In its passage between the drawing rollers and the delivery rollers, the sliver normally passes at uniform speed over the surface of a sliver plate 7 where it is engaged repeatedly by means of a detector member 8.

This detector is formed of sheet metal bent to a shape so as to provide a small counterweight 9 which causes the detector to hang at a small angle to the vertical so that a line joining its pivot 10 to its point of engagement with the sliver is approximately perpendicular to the general line of movement of the sliver.

The detector is pivoted to an arm 11 fixed to a rocker shaft 12 which extends across the width of the machine, part only of which is seen in Figure 2. The shaft 12'is rocked by means of an eccentric 15 driven by means of a gear 16 on the shaft of the delivery roller 5 meshing with a second gearwheel 17. These are both enclosed by means of a cover 18, part of which is broken away to show the gearwheel 16.

The eccentric is connected by means of a rod 22 passing through a bush 23, which is free to rock in a link 24 secured to the shaft 12. The rod 22 is located within the bush 23 by means of a collar 25, which bears against one side of the bush and a compression spring 26 which is located between one side of the bush 23 and a second enlarged collar 27 mounted on the end of the rod 22.

Under normal conditions, the force in the rod is insufficient to compress the spring 26 which, therefore, remains in the position shown in Figure l, and the shaft 12 is thereby rocked so as to cause the detector 3 repeatedly to engage the sliver 1 as it passes over the sliver plate 7.

Under normal conditions, as soon as the tip of the detector 8 engages the sliver it is carried forwardly with it, and as its pivot 10 continues to move downwardly, the detector is rocked in a counter-clockwise direction as shown in Figure 3, which shows the detector at the eX-. treme end of its stroke. On the return stroke, the detector slides back along the surface of the sliver, and when it reaches again the position of Figure 1, is lifted clear of the sliver until the other end of the stroke is reached. Thus under normal operation, the detector repeatedly engages the sliver and by virtue of the motion of the sliver is rocked about its pivot so that its tip moves backwards and forwards along an L-shaped path.

Under fault conditions, however, which may be when the sliver is missing altogether, when it is stationary or when it is moving at a greatly reduced speed as already described in detail, the detector is not rocked about its pivot and consequently comes into engagement with the sliver plate 7, which functions as an abutment. If as shown in Figure 4 the sliver is missing altogether, the engagement between the detector and the sliver plate is direct whereas if the sliver is still present, the engagement is indirect, being through the sliver itself. In order to ensure that the tip of the detector does not slide along the surface of the sliver plate, the latter is formed with a small depression 30, and as soon as the tip of the detector moves into this depression, its motion is positively stopped and as a consequence the motion of the shaft 12 is correspondingly interrupted. Since, however, the connecting rod 22 continues to move to the right as seen in Figure l, the spring 26 is compressed and the collar 27 moves to the right in relation to the bush 23 to exert a camming action on the left-hand face of an arm 31 pivoted at 32 to the bush 23. Under normal conditions, the weight of this arm tends to turn it in a counter-clockwise direction where it is supported by the collar 27, but as the collar 27 moves to the right so the arm is rocked in a clockwise direction and its opposite end 33 then moves downwardly and to the left to engage the plunger of a small enclosed micro'action switch 34 which operates to stop the machine as seen in Figure 4.

In the modification shown in Figures 5 to 7, the components of the drawing frame are the same and are indicated by the same reference numerals, but the relative movement producing engagement of the detector with the sliver is brought about by means of transverse movement of the sliver. For this purpose, the sliver i is led over a sliver plate 37 pivoted at 38 and caused to rock about the pivot by means of a link 39 driven from an eccentric 40. As the sliver plate rocks, so the sliver passing over it is given a transverse component to its motion and is brought into engagement with a detector 45 of the same shape as the detector 8 of Figure 1, piv- Ioted at 46. The pivot 46 is mounted on an arm 47 which can rock about an axis 48, but which is held in the position shown in Figure 5 by means of a stop.

In normal operation, as soon as the sliver moves upwardly far enough to bring it into engagement with the detector 45, the end of the detector is brushed in a sideways direction' as shown in Figure 6, causing the detector to rock about its pivot 46 in a counter-clockwise direction as shown in Figure 6. As the sliver moves downwardly again, the tip of the detector retraces its path, and as a result moves backwards and forwards along an L-shaped path. If, however, the sliver is missing altogether as shown in Figure 7, or alternatively is stationary or is running at a speed below its critical value, the upward movement of the sliver plate 37 forces the detector 45 upwardly and rocks the arm 47 away from its stop and into contact with a small enclosed microaction switch 50 to stop the machine. It will be understood, therefore, that the detector itself behaves in exactly the same manner as in the construction of Figures 1 to 4, and as soon as the fault condition arises, the switch 50 is operated to stop the machine.

The arrangement shown in Figure 8 is a further modification of that shown in Figure 1. In this case the detector shown as 55 is pivoted at 56 to a bracket 57 which is rocked by means of a rocker shaft 58 (corresponding to the rocker shaft 12 in Figure 1) so as to cause the detector to reciprocate and repeatedly engage the sliver as in the construction of Figure 1. In this case, the sliver is shown as passing over a conductor 60 which extends between the drawing rollers 3 and 4 and the delivery rollers 5 and 6. Thus in normal operation, the tip of the detector moves backwards and forwards along its L-shaped path, but as soon as the sliver is missing or its speed falls below the critical value, the tip of the detector comes into engagement with the conductor 60, thus stopping the rocking of the shaft 58 and operating a switch 34 by means of an arm 31 as in Figure 1.

In addition to this operation, however, the stop mechanism is designed to operate when a choke forms as shown in the figure. For this purpose, the bracket 57 is formed with a nose 61 which reciprocates above the normal path of motion of the sliver. When, however, a choke forms as shown at 62 the sliver builds up between the pressing roller 4, the conductor 60 and the nose 61. Finally as the sliver becomes packed tighter and tighter, the reciprocating motion of the nose is interrupted, thus stopping the rocking of the shaft 58 and once again bringing the stop mechanism into action. Thus this form of stop mechanism operates equally well on all fault conditions.

I claim:

1. In a textile machine including means defining a path along which fibrous material travels at uniform speed, the combination of a detector, pivot means for said detector, means for producing relative motion between said detector and said fibrous material to cause repeated engagement between said detector and said fibrous material, said relative motion having a component transverse to the general direction of travel of said fibrous material, an abutment, said abutment being so situated in relation to said detector that when the fibrous material is moving at a speed greater than a critical value in relation to the transverse component of said relative motion, said detector is rocked about said pivot means so as to avoid engaging said abutment, while under other conditions a part of said detector engages said abutment,

a stopping device, and means operated by engagement between said detector and said abutment for operating said stopping device.

2. In a textilemachine having a pair of drawing rollers adapted to deliver sliver across a space at uniform speed, the combination of a detector, pivot means for said detector, means for cyclically moving said detector whereby said detector repeatedly engages said sliver in said a stopping device, and means operated by engagement,

between said detector and said abutment for operating said stopping device.

3. A textile machine according to claim 2, in which said abutment is fixed and also including a yieldable connection between said moving means and said detector, and means responsive to yielding of said connection for operating said stopping device.

4. In a textile machine having a pair of drawing rollers adapted to deliver sliver across a space at uniform speed, the combination of a rocker shaft, a radial arm projecting from said rocker shaft, a detector pivoted to said arm, means for rocking said rocker shaft whereby said detector is caused to reciprocate so as repeatedly to engage said sliver in said space with a component of motion transverse to that of said sliver, an abutment in said space, said abutment being so situated in relation to said detector that when the sliver is moving at a speed greater than a critical value in relation to the transverse component of said relative motion, said detector is rocked by said sliver about said pivot means so as to avoid engaging said abutment, while under other conditions a part of said detector engages said abutment so as to stop movement of said rocker shaft, a stopping device, and means responsive to stoppage of said rocker shaft for operating said stopping device.

5. A textile machine according to claim 4, in which said rocking means comprises an eccentric, means for driving said eccentric, a rod connected to said eccentric, a second radial arm on said rocker shaft, a spring transmitting the movement of said rod to said second arm, and cam means responsive to distortion of said spring conse quent on stoppage of said rocker shaft, said cam means being operative to stop said machine.

6. A textile machine according to claim 5 wherein said stopping device includes an electric switch operated by said cam means.

7. A textile machine according to claim 5 and also including a third arm fixed to said rocker shaft, said third arm being thus normally caused to reciprocate above the path of said sliver but being so situated as to have its motion stopped in the event of a choke.

8. In a textile machine having a pair of drawing rollers adapted to deliver sliver along a customary path, the combination of a detector adjacent to said path, pivot means for said detector, support means for said sliver, means for imparting transverse reciprocating movement to said support means and hence to said sliver, whereby said sliver repeatedly engages said detector so that when the sliver is moving at a speed greater than the critical value in relation to the transverse reciprocating motion, said detector is rocked about said pivot means, while under other conditions said detector engages said support means, and means responsive to engagement between said detector and said support means for stopping said machine.

9. A textile machine according to claim 8, in which said pivot means of said detector is normally stationary and includes yieldable means whereby said pivot means is displaced when said support means engages said detector, and said stopping means includes a device responsive to said displacement of said pivot means.

10. In a textile machine including means defining a path of travel for fibrous material across a space at a desired rate of speed, the combination of a detector, pivot means for said detector, means for cyclically moving said detector whereby said detector repeatedly engages said fibrous material in said space with a component of motion transverse to that of said fibrous material, an abutment in said space, said abutment being so situated in relation to said detector that when the fibrous material is moving at a speed greater than a critical value in relation to the transverse component of said relative motion, said detector is rocked about said pivot means so as to avoid engaging said abutment, while under other conditions a part of said detector engages said abutment, a stopping device, and means operated by engagement between said detector and said abutment for operating said stopping device.

11. In a textile machine including means defining a path of travel for fibrous material along a customary path, the combination of a detector adjacent to said path, pivot means for said detector, support means for said fibrous material, means for imparting transverse reciprocating movement to said support means and hence to said fibrous material, whereby said fibrous material repeatedly engages said detector so that when the fibrous material is moving at a speed greater than the critical value in relation to the transverse reciprocating motion, said detector is rocked about said pivot means, while under other conditions said detector engages said support means, and means responsive to engagement between said detector and said support means for stopping said machine.

References Cited in the file of this patent UNITED STATES PATENTS 1,205,506 Bentley Nov. 21, 1916' 1,252,097 Dockray Jan. 1, 1918 1,494,829 Woodcock May 20, 1924 

